For use in sensing the vibration of shafts, for example, of large rotating machinery, a proximity sensor is utilized. Such sensor has a metal case which contains a sensing coil at one end and has a coaxial cable extending out of the other end of the case for connecting to an electrical processing unit. By well known techniques eccentric movement of the shaft, indicating unwanted vibration, can be sensed. This provides an indication of incipient problems. Such a system with a proximity sensor is at the present time being sold by the assignee of this application, Bently Nevada Corporation of Minden, Nev. The proximity sensor itself is being sold under the trademark "Proximitor."
Such a proximity sensor, in addition to the foregoing, includes a coaxial or even triaxial cable connecting the coil and metal case of the proximity sensor with the electrical processing unit. Because of very adverse ambient conditions, such sensor--besides being resistant to heat and moisture--must withstand mechanical stresses such as pulling or twisting on the coaxial cable. Because of the relatively fine wire (for example, 0.0035" in diameter) of the sensing coil, breakage has sometimes occurred in the past.